Inbred sweet corn line I880S

ABSTRACT

An inbred sweet corn line, designated 1880S, is disclosed. The invention relates to the seeds of inbred corn line 1880S, to the plants of inbred corn line 1880S and to methods for producing a corn plant, either inbred or hybrid, by crossing the inbred line 1880S with itself or another corn line. The invention further relates to methods for producing a corn plant containing in its genetic material one or more transgenes and to the transgenic plants produced by that method and to methods for producing other inbred corn lines derived from the inbred 1880S.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a new and distinctive sweet corninbred line, designated 1880S. There are numerous steps in thedevelopment of any novel, desirable plant germplasm. Plant breedingbegins with the analysis and definition of problems and weaknesses ofthe current germplasm, the establishment of program goals, and thedefinition of specific breeding objectives. The next step is selectionof germplasm that possess the traits to meet the program goals. The goalis to combine in a single variety or hybrid an improved combination ofdesirable traits from the parental germplasm. These important traits mayinclude higher yield, resistance to diseases and insects, better stalksand roots, tolerance to drought and heat, reduction of the time to cropmaturity, improved eating and processing qualities as well as betteragronomic quality. With mechanical harvesting of many crops, uniformityof plant characteristics such as germination and stand establishment,growth rate, maturity and plant and ear height is important.

[0002] Choice of breeding or selection methods depends on the mode ofplant reproduction, the heritability of the trait(s) being improved, andthe type of cultivar used commercially (e.g., F₁ hybrid cultivar,pureline cultivar, etc.). For highly heritable traits, a choice ofsuperior individual plants evaluated at a single location will beeffective, whereas for traits with low heritability, selection should bebased on mean values obtained from replicated evaluations of families ofrelated plants. Popular selection methods commonly include pedigreeselection, modified pedigree selection, mass selection, and recurrentselection.

[0003] The complexity of inheritance influences choice of the breedingmethod. Backcross breeding is used to transfer one or a few favorablegenes for a highly heritable trait into a desirable cultivar. Thisapproach has been used extensively for breeding disease-resistantcultivars. Various recurrent selection techniques are used to improvequantitatively inherited traits controlled by numerous genes. The use ofrecurrent selection in self-pollinating crops depends on the ease ofpollination, the frequency of successful hybrids from each pollination,and the number of hybrid offspring from each successful cross.

[0004] Each breeding program should include a periodic, objectiveevaluation of the efficiency of the breeding procedure. Evaluationcriteria vary depending on the goal and objectives, but should includegain from selection per year based on comparisons to an appropriatestandard, overall value of the advanced breeding lines, and number ofsuccessful cultivars produced per unit of input (e.g., per year, perdollar expended, etc.).

[0005] Promising advanced breeding lines are thoroughly tested andcompared to appropriate standards in environments representative of thecommercial target area(s) for three years at least. The best lines arecandidates for new commercial cultivars; those still deficient in a fewtraits are used as parents to produce new populations for furtherselection.

[0006] These processes, which lead to the final step of marketing anddistribution, usually take from eight to 12 years from the time thefirst cross is made. Therefore, development of new cultivars is atime-consuming process that requires precise forward planning, efficientuse of resources, and a minimum of changes in direction.

[0007] A most difficult task is the identification of individuals thatare genetically superior, because for most traits the true genotypicvalue is masked by other confounding plant traits or environmentalfactors. One method of identifying a superior plant is to observe itsperformance relative to other experimental plants and to a widely grownstandard cultivar. If a single observation is inconclusive, replicatedobservations provide a better estimate of its genetic worth.

[0008] The goal of plant breeding is to develop new, unique and superiorsweet corn inbred lines and hybrids. The breeder initially selects andcrosses two or more parental lines, followed by repeated selfing andselection, producing many new genetic combinations. The breeder cantheoretically generate billions of different genetic combinations viacrossing, selfing and mutations. The breeder has no direct control atthe cellular level. Therefore, two breeders will never develop the sameline, or even very similar lines, having the same corn traits.

[0009] Each year, the plant breeder selects the germplasm to advance tothe next generation. This germplasm is grown under unique and differentgeographical, climatic and soil conditions, and further selections arethen made, during and at the end of the growing season. The inbred lineswhich are developed are unpredictable. This unpredictability is becausethe breeder's selection occurs in unique environments, with no controlat the DNA level (using conventional breeding procedures), and withmillions of different possible genetic combinations being generated. Abreeder of ordinary skill in the art cannot predict the final resultinglines he develops, except possibly in a very gross and general fashion.The same breeder cannot produce the same line twice by using the exactsame original parents and the same selection techniques. Thisunpredictability results in the expenditure of large research monies todevelop a superior new sweet corn inbred line.

[0010] The development of commercial sweet corn hybrids requires thedevelopment of homozygous inbred lines, the crossing of these lines, andthe evaluation of the crosses. Pedigree breeding and recurrent selectionbreeding methods are used to develop inbred lines from breedingpopulations. Breeding programs combine desirable traits from two or moreinbred lines or various broad-based sources into breeding pools fromwhich inbred lines are developed by selfing and selection of desiredphenotypes. The new inbreds are crossed with other inbred lines and thehybrids from these crosses are evaluated to determine which havecommercial potential.

[0011] Pedigree breeding is used commonly for the improvement ofself-pollinating crops or inbred lines of cross-pollinating crops. Twoparents which possess favorable, complementary traits are crossed toproduce an F₁. An F₂ population is produced by selfing one or severalF₁'s or by intercrossing two F₁'s (sib mating). Selection of the bestindividuals is usually begun in the F₂ population; then, beginning inthe F₃, the best individuals in the best families are selected.Replicated testing of families, or hybrid combinations involvingindividuals of these families, often follows in the F₄ generation toimprove the effectiveness of selection for traits with low heritability.At an advanced stage of inbreeding (i.e., F₆ and F₇), the best lines ormixtures of phenotypically similar lines are tested for potentialrelease as new cultivars.

[0012] Mass and recurrent selections can be used to improve populationsof either self- or cross-pollinating crops. A genetically variablepopulation of heterozygous individuals is either identified or createdby intercrossing several different parents. The best plants are selectedbased on individual superiority, outstanding progeny, or excellentcombining ability. The selected plants are intercrossed to produce a newpopulation in which further cycles of selection are continued.

[0013] Backcross breeding has been used to transfer genes for a simplyinherited, highly heritable trait into a desirable homozygous cultivaror inbred line which is the recurrent parent. The source of the trait tobe transferred is called the donor parent. The resulting plant isexpected to have the attributes of the recurrent parent (e.g., cultivar)and the desirable trait transferred from the donor parent. After theinitial cross, individuals possessing the phenotype of the donor parentare selected and repeatedly crossed (backcrossed) to the recurrentparent. The resulting plant is expected to have the attributes of therecurrent parent (e.g., cultivar) and the desirable trait transferredfrom the donor parent.

[0014] Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in one of several referencebooks (e.g., “Principles of Plant Breeding” John Wiley and Son, pp.115-161, 1960; Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr,1987).

[0015] Proper testing should detect any major faults and establish thelevel of superiority or improvement over current cultivars. In additionto showing superior performance, there must be a demand for a newcultivar that is compatible with industry standards or which creates anew market. The introduction of a new cultivar will incur additionalcosts to the seed producer, the grower, processor and consumer; forspecial advertising and marketing, altered seed and commercialproduction practices, and new product utilization. The testing precedingrelease of a new cultivar should take into consideration research anddevelopment costs as well as technical superiority of the finalcultivar. For seed-propagated cultivars, it must be feasible to produceseed easily and economically.

[0016] Once the inbreds that give the best hybrid performance have beenidentified, the hybrid seed can be reproduced indefinitely as long asthe homogeneity of the inbred parent is maintained. A single-crosshybrid is produced when two inbred lines are crossed to produce the F₁progeny. A double-cross hybrid is produced from four inbred linescrossed in pairs (A×B and C×D) and then the two F₁ hybrids are crossedagain (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁ hybrids islost in the next generation (F₂). Consequently, seed from hybridvarieties is not used for planting stock.

[0017] Hybrid sweet corn seed is typically produced by a male sterilitysystem incorporating manual or mechanical detasseling. Alternate stripsof two sweet corn inbreds are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female). Providing thatthere is sufficient isolation from sources of foreign corn pollen, theears of the detasseled inbred will be fertilized only from the otherinbred (male), and the resulting seed is therefore hybrid and will formhybrid plants.

[0018] The laborious, and occasionally unreliable, detasseling processcan be avoided by using cytoplasmic male-sterile (CMS) inbreds. Plantsof a CMS inbred are male sterile as a result of factors resulting fromthe cytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent incorn plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Seed fromdetasseled fertile corn and CMS produced seed of the same hybrid can beblended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

[0019] There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., U.S. Pat. No. 5,432,068 havedeveloped a system of nuclear male sterility which includes: identifyinga gene which is critical to male fertility, silencing this native genewhich is critical to male fertility; removing the native promoter fromthe essential male fertility gene and replacing it with an induciblepromoter; inserting this genetically engineered gene back into theplant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

[0020] There are many other methods of conferring genetic male sterilityin the art, each with its own benefits and drawbacks. These methods usea variety of approaches such as delivering into the plant a geneencoding a cytotoxic substance associated with a male tissue specificpromoter or an anti-sense system in which a gene critical to fertilityis identified and an antisense to that gene is inserted in the plant(see, Fabinjanski, et al. EPO 89/3010153.8 publication no. 329, 308 andPCT application PCT/CA90/00037 published as WO 90/08828).

[0021] Another version useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, G. R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificallyoften limit the usefulness of the approach.

[0022] Sweet corn is an important and valuable vegetable crop. Thus, acontinuing goal of plant breeders is to develop stable, high yieldingsweet corn hybrids that are agronomically sound. The reasons for thisgoal are obviously to maximize the amount of ears or kernels produced onthe land used and to supply food for humans. To accomplish this goal,the corn breeder must select and develop sweet corn plants that have thetraits that result in superior parental lines for producing hybrids.

SUMMARY OF THE INVENTION

[0023] According to the invention, there is provided a novel inbredsweet corn line, designated 1880S. This invention thus relates to theseeds of inbred sweet corn line 1880S, to the plants of inbred sweetcorn line 1880S and to methods for producing a sweet corn plant producedby crossing the inbred line 1880S with itself or another corn line, andto methods for producing a corn plant containing in its genetic materialone or more transgenes and to the transgenic sweet corn plants producedby that method. This invention also relates to methods for producingother inbred sweet corn lines derived from inbred sweet corn line 1880Sand to the inbred sweet corn lines derived by the use of those methods.This invention further relates to hybrid sweet corn seeds and plantsproduced by crossing the inbred line 1880S with another corn line.

[0024] The inbred sweet corn plant of the invention may furthercomprise, or have, a cytoplasmic factor or other factor that is capableof conferring male sterility. Parts of the corn plant of the presentinvention are also provided, such as e.g., pollen obtained from aninbred plant and an ovule of the inbred plant.

[0025] In another aspect, the present invention provides regenerablecells for use in tissue culture or inbred corn plant 1880S. The tissueculture will preferably be capable of regenerating plants having thephysiological and morphological characteristics of the foregoing inbredsweet corn plant, and of regenerating plants having substantially thesame genotype as the foregoing inbred sweet corn plant. Preferably, theregenerable cells in such tissue cultures will be embryos, protoplasts,meristematic cells, callus, pollen, leaves, anthers, roots, root tips,silk, flowers, kernels, ears, cobs, husks or stalks. Still further, thepresent invention provides sweet corn plants regenerated from the tissuecultures of the invention.

[0026] Another objective of the invention is to provide methods forproducing other inbred sweet corn plants derived from inbred sweet cornline 1880S. Inbred sweet corn lines derived by the use of those methodsare also part of the invention.

[0027] The invention also relates to methods for producing a sweet cornplant containing in its genetic material one or more transgenes and tothe transgenic sweet corn plant produced by that method.

[0028] In another aspect, the present invention provides for single geneconverted plants of 1880S. The single transferred gene may preferably bea dominant or recessive allele. Preferably, the single transferred genewill confer such trait as male sterility, herbicide resistance, insectresistance, resistance for bacterial, fungal, or viral disease, malefertility, enhanced nutritional quality and industrial usage. The singlegene may be a naturally occurring maize gene or a transgene introducedthrough genetic engineering techniques.

[0029] The invention further provides methods for developing sweet cornplant in a sweet corn plant breeding program using plant breedingtechnique including recurrent selection, backcrossing, pedigreebreeding, restriction fragment length polymorphism enhanced selection,genetic marker enhanced selection and transformation. Seeds, corn plant,and parties thereof produced by such breeding methods are also part ofthe invention.

DEFINITIONS

[0030] In the description and tables which follow, a number of terms areused. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

[0031] Allele. The allele is any of one or more alternative form of agene, all of which alleles relates to one trait or characteristic. In adiploid cell or organism, the two alleles of a given gene occupycorresponding loci on a pair of homologous chromosomes.

[0032] Backcrossing. Backcrossing is a process in which a breederrepeatedly crosses hybrid progeny back to one of the parents, forexample, a first generation hybrid F₁ with one of the parental genotypeof the F₁ hybrid.

[0033] Essentially all the physiological and morphologicalcharacteristics. A plant having essentially all the physiological andmorphological characteristics means a plant having the physiological andmorphological characteristics, except for the characteristics derivedfrom the converted gene.

[0034] Regeneration. Regeneration refers to the development of a plantfrom tissue culture.

[0035] Single gene converted. Single gene converted or conversion plantrefers to plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of an inbred are recovered in additionto the single gene transferred into the inbred via the backcrossingtechnique or via genetic engineering.

[0036] Daily heat unit value. The daily heat unit value is calculated asfollows: (the maximum daily temperature+the minimum daily temperature)/2minus 50. All temperatures are in degrees Fahrenheit. The maximumtemperature threshold is 86 degrees, if temperatures exceed this, 86 isused. The minimum temperature threshold is 50 degrees, if temperaturesgo below this, 50 is used.

[0037] Endosperm Type. Endosperm type refers to endosperm genes andtypes such as starch, sugary alleles (su1, su2, etc.), sugary enhanceror extender, waxy, amylose extender, dull, brittle alleles (bt1, bt2,etc.) other sh2 alleles, and any combination of these.

[0038] Yield. The yield is the tons of green corn or green weight peracre, It can also be defined as the number of ears per acre or perplant.

[0039] Moisture. The moisture is the actual percentage moisture of thegrain at harvest.

[0040] HTU. HTU is the summation of the daily heat unit value calculatedfrom emergence to harvest.

[0041] Quantitative Trait Loci (QTL) Quantitative trait loci refer togenetic loci that control to some degree numerically representabletraits that are usually continuously distributed.

[0042] Root Lodging. The root lodging is the percentage of plants thatroot lodge; i.e., those that lean from the vertical axis at anapproximate 300 angle or greater would be counted as root lodged.

[0043] Stay Green. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Inbred corn line 1880S is a yellow corn with a sh2 endosperm andsuperior characteristics, and provides an excellent parental line incrosses for producing first generation (F₁) hybrid corn. Inbred cornline 1880S is best adapted to the Northwest of the US (Washington,Idaho) for seed production as it makes a good female. Resulting hybridsare main to mid season maturity (75 to 85 maturity days from planting toharvest) and are best suited for the shipping markets in the Southwest,Northeast, North Central and West Coast sweet corn production areas.Inbred corn line 1880S shows a good seedling vigor, a good seed quality,excellent husk cover, above average stay green, excellent pollen shed,medium flag leaves, good ear shape, good kernel rowing, Rp1d common rustresistance, Maize Dwarf Mosaic Virus (MDMV) resistance and tolerance toStewart's Wilt. It has a very good plant habit with a strong stalk forseason long standability.

[0045] 1880S is similar to 1301S, however there are numerous differencesincluding the fact that 1880S flowers earlier than 1301S. 1880S has alsoimproved disease resistances; it has Rp1d resistance to common rustwhile 1301S does not. 1880S also shows improved resistance to MDMV andStewart's Wilt when compared to 1301S. Further, 1880S has better seedquality and ear size than 1301S and is an improved female parent.

[0046] 1880S has a plant height of 164 cm with an average ear insertionof 54 cm. 1880S is a main season inbred and is well adapted for use as afemale or male in seed production. This sweet corn inbred contributes tohigh yield, easy picking, dark green husks in a shipping hybrid. Thekernels are arranged in distinct and slightly curved rows on the ear.Heat units to 50% pollen shed are approximately 1292 and to 50% silk areapproximately 1349.

[0047] 1880S is an inbred line with high yield potential and very strongstalk and roots in hybrids. For an inbred of its maturity, 1880S resultsin hybrids with well filled ears, with dark green husk and very goodhusk protection. Often these hybrid combinations results in plants whichare of much better than average overall health when compared to inbredlines of similar maturity.

[0048] Some of the criteria used to select ears in various generationsinclude: yield, stalk quality, root quality, disease tolerance, lateplant greenness, late season plant intactness, kernel rowing, strong tipfill, ear shape and size, seed quality, eating quality, ear height,pollen shedding ability, silking ability, and corn borer tolerance.During the development of the line, crosses were made to inbred testersfor the purpose of estimating the line's general and specific combiningability, and parallel evaluations were run in the USA in Bell Glade,Fla., Sun Prairie, Wis. and Nampa, Id. The inbred was evaluated furtheras a line and in numerous crosses by the Nampa station. The inbred hasproven to have a good combining ability in hybrid combinations.

[0049] The inbred line has shown uniformity and stability for thetraits, within the limits of environmental influence for the traits. Ithas been self-pollinated a sufficient number of generations with carefulattention to uniformity of plant type. The line has been increased withcontinued observation for uniformity. No variant traits have beenobserved or are expected in 1880S.

[0050] Inbred corn line 1880S has the following morphologic and othercharacteristics (based primarily on data collected at Bell Glade, Fla.,Sun Prairie, Wis., Los Mochis, Mexico and Nampa, Id.).

Variety Description Information

[0051] VARIETY DESCRIPTION INFORMATION TYPE: Inbred REGION WHEREDEVELOPED: WI, ID and Mexico. VIGOR (from 1 = very weak to 5 = verystrong): 2.4 MATURITY: Days From planting to 50% of plants in tassel: 72From planting to 50% of plants in silk: 74 PLANT: Plant Height to tasseltip: 164 cm Ear Height to base of top ear: 54 cm Average number ofTillers: 1.1 Average Number of Ears per Stalk: 1.5 Anthocyanin of BraceRoots: None LEAF: Width of Ear Node Leaf: 7.37 cm Length of Ear NodeLeaf: 69.47 cm Leaf Angle (from 2nd Leaf above ear at anthesis to Stalkabove leaf): 40° Leaf Sheath Pubescence (Rate on scale from 1 = none to9 = like peach fuzz): 3.6 Marginal Waves (Rate on scale from 1 = none to9 = many): 3.6 Longitudinal Creases (Rate on scale from 1 = none to 9 =many): 5 TASSEL: Number of Lateral Branches: 32.4 Branch Angle fromCentral Spike: 45° Tassel Length (from top leaf collar to tassel top):12.82 cm Anther Color: Yellow Glume Color: Green EAR: (Unhusked Data)Number of Flag leaves: 3.2 Average length of flags: 7.75 cm Averagewidth of flags: 1.68 cm Silk Color (3 days after emergence): Yellow HuskCover at harvest: 11.05 cm EAR: (Husked Ear Data) Ear Length: 15.62 cmEar Diameter at mid-point: 3.68 mm Number of Kernel Rows: 15.2 RowAlignment (from 1 very crooked to 9 very straight): 6 Shank Length:13.97 cm Ear Shape: Cylindrical to slightly tapered KERNEL: (Dried)Kernel color: yellow Endosperm Type: sh2 COB: Cob Color: white DISEASERESISTANCE Rating (1 = susceptible-5 = resistant) Common Rust 3.7 MaizeDwarf Mosaic 4.3 Northern Leaf Blight 2.5 Stewart's Wilt Resistance 3.3

FURTHER EMBODIMENTS OF THE INVENTION

[0052] This invention also is directed to methods for producing a sweetcorn plant by crossing a first parent corn plant with a second parentcorn plant wherein either the first or second parent corn plant is aninbred corn plant of the line 1880S. Further, both first and secondparent corn plants can come from the inbred corn line 1880S. Stillfurther, this invention also is directed to methods for producing aninbred corn line 1880S-derived corn plant by crossing inbred corn line1880S with a second corn plant and growing the progeny seed, andrepeating the crossing and growing steps with the inbred corn line1880S-derived plant from 0 to 7 times. Thus, any such methods using theinbred corn line 1880S are part of this invention: selfing, backcrosses,hybrid production, crosses to populations, and the like. All plantsproduced using inbred corn line 1880S as a parent are within the scopeof this invention, including plants derived from inbred corn line 1880S.Advantageously, the inbred corn line is used in crosses with other,different, corn inbreds to produce first generation (F₁) corn hybridseeds and plants with superior characteristics.

[0053] It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

[0054] As used herein, the term plant includes plant cells, plantprotoplasts, plant cell tissue cultures from which corn plants can beregenerated, plant calli, plant clumps and plant cells that are intactin plants or parts of plants, such as embryos, pollen, ovules, flowers,kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers,silk and the like.

[0055] Duncan, et al., Planta 165:322-332 (1985) reflects that 97% ofthe plants cultured that produced callus were capable of plantregeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus that produced plants. In a further studyin 1988, Songstad, et al., Plant Cell Reports 7:262-265 (1988), reportsseveral media additions that enhance regenerability of callus of twoinbred lines. Other published reports also indicated that“nontraditional” tissues are capable of producing somatic embryogenesisand plant regeneration. K. P. Rao et al., Maize Genetics CooperationNewsletter, 60:64-65 (1986), refers to somatic embryogenesis from glumecallus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347(1987) indicates somatic embryogenesis from the tissue cultures of cornleaf segments. Thus, it is clear from the literature that the state ofthe art is such that these methods of obtaining plants are, and were,“conventional” in the sense that they are routinely used and have a veryhigh rate of success.

[0056] Tissue culture of corn is described in European PatentApplication, publication 160,390, incorporated herein by reference. Corntissue culture procedures are also described in Green and Rhodes, “PlantRegeneration in Tissue Culture of Maize,” Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 367-372,(1982)) and in Duncan et al., “The Production of Callus Capable of PlantRegeneration from Immature Embryos of Numerous Zea Mays Genotypes,” 165Planta 322:332 (1985). Thus, another aspect of this invention is toprovide cells which upon growth and differentiation produce corn plantshaving the physiological and morphological characteristics of inbredcorn line 1880S.

[0057] The utility of inbred corn line 1880S also extends to crosseswith other species. Commonly, suitable species will be of the familyGraminaceae, and especially of the genera Zea, Tripsacum, Croix,Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribeMaydeae. Potentially suitable for crosses with 1880S may be the variousvarieties of grain sorghum, Sorghum bicolor (L.) Moench.

[0058] With the advent of molecular biological techniques that haveallowed the isolation and characterization of genes that encode specificprotein products, scientists in the field of plant biology developed astrong interest in engineering the genome of plants to contain andexpress foreign genes, or additional, or modified versions of native, orendogenous, genes (perhaps driven by different promoters) in order toalter the traits of a plant in a specific manner. Such foreignadditional and/or modified genes are referred to herein collectively as“transgenes”. Over the last fifteen to twenty years several methods forproducing transgenic plants have been developed, and the presentinvention, in particular embodiments, also relates to transformedversions of the claimed inbred line.

[0059] Plant transformation involves the construction of an expressionvector which will function in plant cells. Such a vector comprises DNAcomprising a gene under control of or operatively linked to a regulatoryelement (for example, a promoter). The expression vector may contain oneor more such operably linked gene/regulatory element combinations. Thevector(s) may be in the form of a plasmid, and can be used alone or incombination with other plasmids, to provide transformed corn plants,using transformation methods as described below to incorporatetransgenes into the genetic material of the corn plant(s).

[0060] Expression Vectors for Corn Transformation

[0061] Marker Genes—Expression vectors include at least one geneticmarker, operably linked to a regulatory element (a promoter, forexample) that allows transformed cells containing the marker to beeither recovered by negative selection, i.e., inhibiting growth of cellsthat do not contain the selectable marker gene, or by positiveselection, i.e., screening for the product encoded by the geneticmarker. Many commonly used selectable marker genes for planttransformation are well known in the transformation arts, and include,for example, genes that code for enzymes that metabolically detoxify aselective chemical agent which may be an antibiotic or a herbicide, orgenes that encode an altered target which is insensitive to theinhibitor. A few positive selection methods are also known in the art.

[0062] One commonly used selectable marker gene for plant transformationis the neomycin phosphotransferase II (nptII) gene, isolated fromtransposon Tn5, which when placed under the control of plant regulatorysignals confers resistance to kanamycin. Fraley et al., Proc. Natl.Acad. Sci. U.S.A., 80:4803 (1983). Another commonly used selectablemarker gene is the hygromycin phosphotransferase gene which confersresistance to the antibiotic hygromycin. Vanden Elzen et al., Plant Mol.Biol., 5:299 (1985).

[0063] Additional selectable marker genes of bacterial origin thatconfer resistance to antibiotics include gentamycin acetyl transferase,streptomycin phosphotransferase, aminoglycoside-3′-adenyl transferase,the bleomycin resistance determinant. Hayford et al., Plant Physiol.86:1216 (1988), Jones et al., Mol. Gen. Genet., 210:86 (1987), Svab etal., Plant Mol. Biol. 14:197 (1990<Hille et al., Plant Mol. Biol. 7:171(1986). Other selectable marker genes confer resistance to herbicidessuch as glyphosate, glufosinate or broxynil. Comai et al., Nature317:741-744 (1985), Gordon-Kamm et al., Plant Cell 2:603-618 (1990) andStalker et al., Science 242:419-423 (1988).

[0064] Other selectable marker genes for plant transformation are not ofbacterial origin. These genes include, for example, mouse dihydrofolatereductase, plant 5-enolpyruvylshikimate-3-phosphate synthase and plantacetolactate synthase. Eichholtz et al., Somatic Cell Mol. Genet. 13:67(1987), Shah et al., Science 233:478 (1986), Charest et al., Plant CellRep. 8:643 (1990).

[0065] Another class of marker genes for plant transformation requirescreening of presumptively transformed plant cells rather than directgenetic selection of transformed cells for resistance to a toxicsubstance such as an antibiotic. These genes are particularly useful toquantify or visualize the spatial pattern of expression of a gene inspecific tissues and are frequently referred to as reporter genesbecause they can be fused to a gene or gene regulatory sequence for theinvestigation of gene expression. Commonly used genes for screeningpresumptively transformed cells include â-glucuronidase (GUS,â-galactosidase, luciferase and chloramphenicol, acetyltransferase.Jefferson, R. A., Plant Mol. Biol. Rep. 5:387 (1987), Teeri et al., EMBOJ. 8:343 (1989), Koncz et al., Proc. Natl. Acad. Sci U.S.A. 84:131(1987), DeBlock et al., EMBO J. 3:1681 (1984). Another approach to theidentification of relatively rare transformation events has been use ofa gene that encodes a dominant constitutive regulator of the Zea maysanthocyanin pigmentation pathway. Ludwig et al., Science 247:449 (1990).

[0066] Recently, in vivo methods for visualizing GUS activity that donot require destruction of plant tissue have been made available.Molecular Probes publication 2908, Imagene Green™, p. 1-4 (1993) andNaleway et al., J. Cell Biol. 115:151a (1991). However, these in vivomethods for visualizing GUS activity have not proven useful for recoveryof transformed cells because of low sensitivity, high fluorescentbackgrounds and limitations associated with the use of luciferase genesas selectable markers.

[0067] More recently, a gene encoding Green Fluorescent Protein (GFP)has been utilized as a marker for gene expression in prokaryotic andeukaryotic cells. Chalfie et al., Science 263:802 (1994). GFP andmutants of GFP may be used as screenable markers.

[0068] Promoters—Genes included in expression vectors must be driven bynucleotide sequence comprising a regulatory element, for example, apromoter. Several types of promoters are now well known in thetransformation arts, as are other regulatory elements that can be usedalone or in combination with promoters.

[0069] As used herein, “promoter” includes reference to a region of DNAupstream from the start of transcription and involved in recognition andbinding of RNA polymerase and other proteins to initiate transcription.A “plant promoter” is a promoter capable of initiating transcription inplant cells. Examples of promoters under developmental control includepromoters that preferentially initiate transcription in certain tissues,such as leaves, roots, seeds, fibers, xylem vessels, tracheids, orsclerenchyma. Such promoters are referred to as “tissue-preferred”.Promoters which initiate transcription only in certain tissue arereferred to as “tissue-specific”. A “cell type” specific promoterprimarily drives expression in certain cell types in one or more organs,for example, vascular cells in roots or leaves. An “inducible” promoteris a promoter which is under environmental control. Examples ofenvironmental conditions that may effect transcription by induciblepromoters include anaerobic conditions or the presence of light.Tissue-specific, tissue-preferred, cell type specific, and induciblepromoters constitute the class of “non-constitutive” promoters. A“constitutive” promoter is a promoter which is active under mostenvironmental conditions.

[0070] A. Inducible Promoters

[0071] An inducible promoter is operably linked to a gene for expressionin corn. Optionally, the inducible promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in corn. With an inducible promoter the rate oftranscription increases in response to an inducing agent.

[0072] Any inducible promoter can be used in the instant invention. SeeWard et al., Plant Mol. Biol. 22:361-366 (1993). Exemplary induciblepromoters include, but are not limited to, that from the ACEI systemwhich responds to copper (Meft et al., PNAS 90:4567-4571 (1993)); In2gene from maize which responds to benzenesulfonamide herbicide safeners(Hershey et al., Mol. Gen Genetics 227:229-237 (1991) and Gatz et al.,Mol. Gen. Genetics 243:32-38 (1994)) or Tet repressor from Tn10 (Gatz etal., Mol. Gen. Genetics 227:229-237 (1991). A particularly preferredinducible promoter is a promoter that responds to an inducing agent towhich plants do not normally respond. An exemplary inducible promoter isthe inducible promoter from a steroid hormone gene, the transcriptionalactivity of which is induced by a glucocorticosteroid hormone. Schena etal., Proc. Natl. Acad. Sci. U.S.A. 88:0421 (1991).

[0073] B. Constitutive Promoters

[0074] A constitutive promoter is operably linked to a gene forexpression in corn or the constitutive promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in corn.

[0075] Many different constitutive promoters can be utilized in theinstant invention. Exemplary constitutive promoters include, but are notlimited to, the promoters from plant viruses such as the 35S promoterfrom CaMV (Odell et al., Nature 313:810-812 (1985) and the promotersfrom such genes as rice actin (McElroy et al., Plant Cell 2:163-171(1990)); ubiquitin (Christensen et al., Plant Mol. Biol. 12:619-632(1989) and Christensen et al., Plant Mol. Biol. 18:675-689 (1992)); PEMU(Last et al., Theor. Appl. Genet. 81:581-588 (1991)); MAS (Velten etal., EMBO J. 3:2723-2730 (1984)) and maize H3 histone (Lepetit et al.,Mol. Gen. Genetics 231:276-285 (1992) and Atanassova et al., PlantJournal 2 (3): 291-300 (1992)).

[0076] The ALS promoter, Xba1/NcoI fragment 5′ to the Brassica napusALS3 structural gene (or a nucleotide sequence similarity to saidXba1/NcoI fragment), represents a particularly useful constitutivepromoter. See PCT application WO96/30530.

[0077] C. Tissue-Specific or Tissue-Preferred Promoters

[0078] A tissue-specific promoter is operably linked to a gene forexpression in corn. Optionally, the tissue-specific promoter is operablylinked to a nucleotide sequence encoding a signal sequence which isoperably linked to a gene for expression in corn. Plants transformedwith a gene of interest operably linked to a tissue-specific promoterproduce the protein product of the transgene exclusively, orpreferentially, in a specific tissue.

[0079] Any tissue-specific or tissue-preferred promoter can be utilizedin the instant invention. Exemplary tissue-specific or tissue-preferredpromoters include, but are not limited to, a root-preferred promoter,such as that from the phaseolin gene (Murai et al., Science 23:476-482(1983) and Sengupta-Gopalan et al., Proc. Natl. Acad. Sci. U.S.A.82:3320-3324 (1985)); a leaf-specific and light-induced promoter such asthat from cab or rubisco (Simpson et al., EMBO J. 4(11):2723-2729 (1985)and Timko et al., Nature 318:579-582 (1985)); an anther-specificpromoter such as that from LAT52 (Twell et al., Mol. Gen. Genetics217:240-245 (1989)); a pollen-specific promoter such as that from Zm13(Guerrero et al., Mol. Gen. Genetics 244:161-168 (1993)) or amicrospore-preferred promoter such as that from apg (Twell et al., Sex.Plant Reprod. 6:217-224 (1993).

[0080] Signal Sequences for Targeting Proteins to SubcellularCompartments

[0081] Transport of protein produced by transgenes to a subcellularcompartment such as the chloroplast, vacuole, peroxisome, glyoxysome,cell wall or mitochondroin or for secretion into the apoplast, isaccomplished by means of operably linking the nucleotide sequenceencoding a signal sequence to the 5′ and/or 3′ region of a gene encodingthe protein of interest. Targeting sequences at the 5′ and/or 3′ end ofthe structural gene may determine, during protein synthesis andprocessing, where the encoded protein is ultimately compartmentalized.

[0082] The presence of a signal sequence directs a polypeptide to eitheran intracellular organelle or subcellular compartment or for secretionto the apoplast. Many signal sequences are known in the art. See, forexample Becker et al., Plant Mol. Biol. 20:49 (1992), Close, P. S.,Master's Thesis, Iowa State University (1993), Knox, C., et al.,“Structure and Organization of Two Divergent Alpha-Amylase Genes fromBarley”, Plant Mol. Biol. 9:3-17 (1987), Lerner et al., Plant Physiol.91:124-129 (1989), Fontes et al., Plant Cell 3:483-496 (1991), Matsuokaet al., Proc. Natl. Acad. Sci. 88:834 (1991), Gould et al., J. Cell.Biol. 108:1657 (1989), Creissen et al., Plant J. 2:129 (1991), Kalderon,et al., A short amino acid sequence able to specify nuclear location,Cell 39:499-509 (1984), Steifel, et al., Expression of a maize cell wallhydroxyproline-rich glycoprotein gene in early leaf and root vasculardifferentiation, Plant Cell 2:785-793 (1990).

[0083] Foreign Protein Genes and Agronomic Genes

[0084] With transgenic plants according to the present invention, aforeign protein can be produced in commercial quantities. Thus,techniques for the selection and propagation of transformed plants,which are well understood in the art, yield a plurality of transgenicplants which are harvested in a conventional manner, and a foreignprotein then can be extracted from a tissue of interest or from totalbiomass. Protein extraction from plant biomass can be accomplished byknown methods which are discussed, for example, by Heney and Orr, Anal.Biochem. 114:92-6 (1981).

[0085] According to a preferred embodiment, the transgenic plantprovided for commercial production of foreign protein is corn. Inanother preferred embodiment, the biomass of interest is seed. For therelatively small number of transgenic plants that show higher levels ofexpression, a genetic map can be generated, primarily via conventionalRFLP, PCR and SSR analysis, which identifies the approximate chromosomallocation of the integrated DNA molecule. For exemplary methodologies inthis regard, see Glick and Thompson, Methods in Plant Molecular Biologyand Biotechnology CRC Press, Boca Raton 269:284 (1993). Map informationconcerning chromosomal location is useful for proprietary protection ofa subject transgenic plant. If unauthorized propagation is undertakenand crosses made with other germplasm, the map of the integration regioncan be compared to similar maps for suspect plants, to determine if thelatter have a common parentage with the subject plant. Map comparisonswould involve hybridizations, RFLP, PCR, SSR and sequencing, all ofwhich are conventional techniques.

[0086] Likewise, by means of the present invention, agronomic genes canbe expressed in transformed plants. More particularly, plants can begenetically engineered to express various phenotypes of agronomicinterest. Exemplary genes implicated in this regard include, but are notlimited to, those categorized below:

[0087] 1. Genes That Confer Resistance to Pests or Disease and ThatEncode:

[0088] A. Plant disease resistance genes. Plant defenses are oftenactivated by specific interaction between the product of a diseaseresistance gene (R) in the plant and the product of a correspondingavirulence (Avr) gene in the pathogen. A plant inbred line can betransformed with cloned resistance gene to engineer plants that areresistant to specific pathogen strains. See, for example Jones et al.,Science 266:789 (1994) (cloning of the tomato Cf-9 gene for resistanceto Cladosporium fulvum); Martin et al., Science 262:1432 (1993) (tomatoPto gene for resistance to Pseudomonas syringae pv. Tomato encodes aprotein kinase); Mindrinos et al., Cell 78:1089 (1994) (Arabidopsis RSP2gene for resistance to Pseudomonas syringae).

[0089] B. A Bacillus thuringiensis protein, a derivative thereof or asynthetic polypeptide modeled thereon. See, for example, Geiser et al.,Gene 48:109 (1986), who disclose the cloning and nucleotide sequence ofa Bt ä-endotoxin gene. Moreover, DNA molecules encoding ä-endotoxingenes can be purchased from American Type Culture Collection, Manassas,Va., for example, under ATCC Accession Nos. 40098, 67136, 31995 and31998.

[0090] C. A lectin. See, for example, the disclose by Van Damme et al.,Plant Molec. Biol. 24:25 (1994), who disclose the nucleotide sequencesof several Clivia miniata mannose-binding lectin genes.

[0091] D. A vitamin-binding protein such as avidin. See PCT applicationUS93/06487, the contents of which are hereby incorporated by reference.The application teaches the use of avidin and avidin homologues aslarvicides against insect pests.

[0092] E. An enzyme inhibitor, for example, a protease or proteinaseinhibitor or an amylase inhibitor. See, for example, Abe et al., J.Biol. Chem. 262:16793 (1987) (nucleotide sequence of rice cysteineproteinase inhibitor), Huub et al., Plant Molec. Biol. 21:985 (1993)(nucleotide sequence of cDNA encoding tobacco proteinase inhibitor I),Sumitani et al., Biosci. Biotech. Biochem. 57:1243 (1993) (nucleotidesequence of Streptomyces nitrosporeus á-amylase inhibitor).

[0093] F. An insect-specific hormone or pheromone such as an ecdysteroidand juvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344:458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

[0094] G. An insect-specific peptide or neuropeptide which, uponexpression, disrupts the physiology of the affected pest. For example,see the disclosures of Regan, J. Biol. Chem. 269:9 (1994) (expressioncloning yields DNA coding for insect diuretic hormone receptor), andPratt et al., Biochem. Biophys. Res. Comm. 163:1243 (1989) (anallostatin is identified in Diploptera puntata). See also U.S. Pat. No.5,266,317 to Tomalski et al., who disclose genes encodinginsect-specific, paralytic neurotoxins.

[0095] H. An insect-specific venom produced in nature by a snake, awasp, etc. For example, see Pang et al., Gene 116:165 (1992), fordisclosure of heterologous expression in plants of a gene coding for ascorpion insectotoxic peptide.

[0096] I. An enzyme responsible for a hyper accumulation of amonterpene, a sesquiterpene, a steroid, hydroxamic acid, aphenylpropanoid derivative or another non-protein molecule withinsecticidal activity.

[0097] J. An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTapplication WO 93/02197 in the name of Scott et al., which discloses thenucleotide sequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol. 23:691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hookworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21:673 (1993), who provide the nucleotide sequence ofthe parsley ubi4-2 polyubiquitin gene.

[0098] K. A molecule that stimulates signal transduction. For example,see the disclosure by Botella et al., Plant Molec. Biol. 24:757 (1994),of nucleotide sequences for mung bean calmodulin cDNA clones, and Griesset al., Plant Physiol. 104:1467 (1994), who provide the nucleotidesequence of a maize calmodulin cDNA clone.

[0099] L. A hydrophobic moment peptide. See PCT application WO95/16776(disclosure of peptide derivatives of Tachyplesin which inhibit fungalplant pathogens) and PCT application WO95/18855 (teaches syntheticantimicrobial peptides that confer disease resistance), the respectivecontents of which are hereby incorporated by reference.

[0100] M. A membrane permease, a channel former or a channel blocker.For example, see the disclosure of Jaynes et al., Plant Sci 89:43(1993), of heterologous expression of a cecropin-á, lytic peptide analogto render transgenic tobacco plants resistant to Pseudomonassolanacearum.

[0101] N. A viral-invasive protein or a complex toxin derived therefrom.For example, the accumulation of viral coat proteins in transformedplant cells imparts resistance to viral infection and/or diseasedevelopment effected by the virus from which the coat protein gene isderived, as well as by related viruses. See Beachy et al., Ann. rev.Phytopathol. 28:451 (1990). Coat protein-mediated resistance has beenconferred upon transformed plants against alfalfa mosaic virus, cucumbermosaic virus, tobacco streak virus, potato virus X, potato virus Y,tobacco etch virus, tobacco rattle virus and tobacco mosaic virus. Id.

[0102] O. An insect-specific antibody or an immunotoxin derivedtherefrom. Thus, an antibody targeted to a critical metabolic functionin the insect gut would inactivate an affected enzyme, killing theinsect. Cf. Taylor et al., Abstract #497, Seventh Int'l Symposium onMolecular Plant-Microbe Interactions (Edinburgh, Scotland) (1994)(enzymatic inactivation in transgenic tobacco via production ofsingle-chain antibody fragments).

[0103] P. A virus-specific antibody. See, for example, Tavladoraki etal., Nature 366:469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

[0104] Q. A developmental-arrestive protein produced in nature by apathogen or a parasite. Thus, fungal endo á-1, 4-D-polygalacturonasesfacilitate fungal colonization and plant nutrient release bysolubilizing plant cell wall homo-á-1,4-D-galacturonase. See Lamb etal., Bio/Technology 10:1436 (1992). The cloning and characterization ofa gene which encodes a bean endopolygalacturonase-inhibiting protein isdescribed by Toubart et al., Plant J. 2:367 (1992).

[0105] R. A development-arrestive protein produced in nature by a plant.For example, Logemann et al., Bioi/Technology 10:305 (1992), have shownthat transgenic plants expressing the barley ribosome-inactivating genehave an increased resistance to fungal disease.

[0106] 2. Genes That Confer Resistance to a Herbicide, For Example:

[0107] A. A herbicide that inhibits the growing point or meristem, suchas an imidazalinone or a sulfonylurea. Exemplary genes in this categorycode for mutant ALS and AHAS enzyme as described, for example, by Lee etal., EMBO J. 7:1241 (1988), and Miki et al., Theor. Appl. Genet. 80:449(1990), respectively.

[0108] B. Glyphosate (resistance impaired by mutant5-enolpyruvl-3-phosphikimate synthase (EPSP) and aroA genes,respectively) and other phosphono compounds such as glufosinate(phosphinothricin acetyl transferase, PAT and Streptomyces hygroscopicusphosphinothricin-acetyl transferase, bar, genes), and pyridinoxy orphenoxy propionic acids and cycloshexones (ACCase inhibitor-encodinggenes). See, for example, U.S. Pat. No. 4,940,835 to Shah, et al., whichdiscloses the nucleotide sequence of a form of EPSP which can conferglyphosate resistance. A DNA molecule encoding a mutant aroA gene can beobtained under ATCC accession number 39256, and the nucleotide sequenceof the mutant gene is disclosed in U.S. Pat. No. 4,769,061 to Comai.European patent application No. 0 333 033 to Kumada et al., and U.S.Pat. No. 4,975,374 to Goodman et al., disclose nucleotide sequences ofglutamine synthetase genes which confer resistance to herbicides such asL-phosphinothricin. The nucleotide sequence of aphosphinothricin-acetyl-transferase gene is provided in Europeanapplication No. 0 242 246 to Leemans et al., DeGreef et al.,Bio/Technology 7:61 (1989), describe the production of transgenic plantsthat express chimeric bar genes coding for phosphinothricin acetyltransferase activity. Exemplary of genes conferring resistance tophenoxy propionic acids and cycloshexones, such as sethoxydim andhaloxyfop are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described byMarshall et al., Theor. Appl. Genet. 83:435 (1992).

[0109] C. A herbicide that inhibits photosynthesis, such as a triazine(psbA and gs+ genes) and a benzonitrile (nitrilase gene). Przibilla etal., Plant Cell 3:169 (1991), describe the transformation ofChlamydomonas with plasmids encoding mutant psbA genes. Nucleotidesequences for nitrilase genes are disclosed in U.S. Pat. No. 4,810,648to Stalker, and DNA molecules containing these genes are available underATCC Accession Nos. 53435, 67441, and 67442. Cloning and expression ofDNA coding for a glutathione S-transferase is described by Hayes et al.,Biochem. J. 285:173 (1992).

[0110] 3. Genes That Confer or Contribute to a Value-Added Trait, Suchas:

[0111] A. Modified fatty acid metabolism, for example, by transforming aplant with an antisense gene of stearyl-ACP desaturase to increasestearic acid content of the plant. See Knultzon et al., Proc. Natl.Acad. Sci. U.S.A. 89:2624 (1992).

[0112] B. Decreased Phytate Content

[0113] 1) Introduction of a phytase-encoding gene would enhancebreakdown of phytate, adding more free phosphate to the transformedplant. For example, see Van Hartingsveldt et al., Gene 127:87 (1993),for a disclosure of the nucleotide sequence of an Aspergillus nigerphytase gene.

[0114] 2) A gene could be introduced that reduced phytate content. Inmaize, this, for example, could be accomplished, by cloning and thenreintroducing DNA associated with the single allele which is responsiblefor maize mutants characterized by low levels of phytic acid. See Raboyet al., Maydica 35:383 (1990).

[0115] C. Modified carbohydrate composition effected, for example, bytransforming plants with a gene coding for an enzyme that alters thebranching pattern of starch. See Shiroza et al., J. Bacteol. 170:810(1988) (nucleotide sequence of Streptococcus mutantsfructosyltransferase gene), Steinmetz et al., Mol. Gen. Genet. 20:220(1985) (nucleotide sequence of Bacillus subtilis levansucrase gene), Penet al., Bio/Technology 10:292 (1992) (production of transgenic plantsthat express Bacillus licheniformis á-amylase), Elliot et al., PlantMolec. Biol. 21:515 (1993) (nucleotide sequences of tomato invertasegenes), Søgaard et al., J. Biol. Chem. 268:22480 (1993) (site-directedmutagenesis of barley á-amylase gene), and Fisher et al., Plant Physiol.102:1045 (1993) (maize endosperm starch branching enzyme II).

[0116] Methods for Corn Transformation

[0117] Numerous methods for plant transformation have been developed,including biological and physical, plant transformation protocols. See,for example, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, GlickB. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages67-88. In addition, expression vectors and in vitro culture methods forplant cell or tissue transformation and regeneration of plants areavailable. See, for example, Gruber et al., “Vectors for PlantTransformation” in Methods in Plant Molecular Biology and Biotechnology,Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993)pages 89-119.

[0118] A. Agrobacterium-mediated Transformation

[0119] One method for introducing an expression vector into plants isbased on the natural transformation system of Agrobacterium. See, forexample, Horsch et al., Science 227:1229 (1985). A. tumefaciens and A.rhizogenes are plant pathogenic soil bacteria which geneticallytransform plant cells. The Ti and Ri plasmids of A. tumefaciens and A.rhizogenes, respectively, carry genes responsible for genetictransformation of the plant. See, for example, Kado, C. I., Crit. Rev.Plant Sci. 10:1 (1991). Descriptions of Agrobacterium vector systems andmethods for Agrobacterium-mediated gene transfer are provided by Gruberet al., supra, Miki et al., supra, and Moloney et al., Plant CellReports 8:238 (1989). See also, U.S. Pat. No. 5,591,616 issued Jan. 7,1997.

[0120] B. Direct Gene Transfer

[0121] Despite the fact the host range for Agrobacterium-mediatedtransformation is broad, some major cereal crop species and gymnospermshave generally been recalcitrant to this mode of gene transfer, eventhough some success has recently been achieved in rice and corn. Hiei etal., The Plant Journal 6:271-282 (1994) and U.S. Pat. No. 5,591,616issued Jan. 7, 1997. Several methods of plant transformation,collectively referred to as direct gene transfer, have been developed asan alternative to Agrobacterium-mediated transformation.

[0122] A generally applicable method of plant transformation ismicroprojectile-mediated transformation wherein DNA is carried on thesurface of microprojectiles measuring 1 to 4 im. The expression vectoris introduced into plant tissues with a biolistic device thataccelerates the microprojectiles to speeds of 300 to 600 m/s which issufficient to penetrate plant cell walls and membranes. Sanford et al.,Part. Sci. Technol. 5:27 (1987), Sanford, J. C., Trends Biotech. 6:299(1988), Klein et al., Bio/Technology 6:559-563 (1988), Sanford, J. C.,Physiol Plant 7:206 (1990), Klein et al., Biotechnology 10:268 (1992).In corn, several target tissues can be bombarded with DNA-coatedmicroprojectiles in order to produce transgenic plants, including, forexample, callus (Type I or Type II), immature embryos, and meristematictissue.

[0123] Another method for physical delivery of DNA to plants issonication of target cells. Zhang et al., Bio/Technology 9:996 (1991).Alternatively, liposome or spheroplast fusion have been used tointroduce expression vectors into plants. Deshayes et al., EMBO J.,4:2731 (1985), Christou et al., Proc Natl. Acad. Sci. U.S.A. 84:3962(1987). Direct uptake of DNA into protoplasts using CaCl₂ precipitation,polyvinyl alcohol or poly-L-omithine have also been reported. Hain etal., Mol. Gen. Genet. 199:161 (1985) and Draper et al., Plant CellPhysiol. 23:451 (1982). Electroporation of protoplasts and whole cellsand tissues have also been described. Donn et al., In Abstracts of VIIthInternational Congress on Plant Cell and Tissue Culture IAPTC, A2-38, p53 (1990); D'Halluin et al., Plant Cell 4:1495-1505 (1992) and Spenceret al., Plant Mol. Biol. 24:51-61 (1994).

[0124] Following transformation of corn target tissues, expression ofthe above-described selectable marker genes allows for preferentialselection of transformed cells, tissues and/or plants, usingregeneration and selection methods now well known in the art.

[0125] The foregoing methods for transformation would typically be usedfor producing a transgenic inbred line. The transgenic inbred line couldthen be crossed, with another (non-transformed or transformed) inbredline, in order to produce a new transgenic inbred line. Alternatively, agenetic trait which has been engineered into a particular sweet cornline using the foregoing transformation techniques could be moved intoanother line using traditional backcrossing techniques that are wellknown in the plant breeding arts. For example, a backcrossing approachcould be used to move an engineered trait from a public, non-eliteinbred line into an elite inbred line, or from an inbred line containinga foreign gene in its genome into an inbred line or lines which do notcontain that gene. As used herein, “crossing” can refer to a simple X byY cross, or the process of backcrossing, depending on the context.

[0126] When the term inbred corn plant is used in the context of thepresent invention, this also includes any single gene conversions ofthat inbred. The term single gene converted plant as used herein refersto those sweet corn plants which are developed by a plant breedingtechnique called backcrossing wherein essentially all of the desiredmorphological and physiological characteristics of an inbred arerecovered in addition to the single gene transferred into the inbred viathe backcrossing technique. Backcrossing methods can be used with thepresent invention to improve or introduce a characteristic into theinbred. The term backcrossing as used herein refers to the repeatedcrossing of a hybrid progeny back to one of the parental corn plants forthat inbred. The parental corn plant which contributes the gene for thedesired characteristic is termed the nonrecurrent or donor parent. Thisterminology refers to the fact that the nonrecurrent parent is used onetime in the backcross protocol and therefore does not recur. Theparental sweet corn plant to which the gene or genes from thenonrecurrent parent are transferred is known as the recurrent parent asit is used for several rounds in the backcrossing protocol (Poehlman &Sleper, 1994; Fehr, 1987). In a typical backcross protocol, the originalinbred of interest (recurrent parent) is crossed to a second inbred(nonrecurrent parent) that carries the single gene of interest to betransferred. The resulting progeny from this cross are then crossedagain to the recurrent parent and the process is repeated until a sweetcorn plant is obtained wherein essentially all of the desiredmorphological and physiological characteristics of the recurrent parentare recovered in the converted plant, in addition to the singletransferred gene from the nonrecurrent parent.

[0127] The selection of a suitable recurrent parent is an important stepfor a successful backcrossing procedure. The goal of a backcrossprotocol is to alter or substitute a single trait or characteristic inthe original inbred. To accomplish this, a single gene of the recurrentinbred is modified or substituted with the desired gene from thenonrecurrent parent, while retaining essentially all of the rest of thedesired genetic, and therefore the desired physiological andmorphological, constitution of the original inbred. The choice of theparticular nonrecurrent parent will depend on the purpose of thebackcross, one of the major purposes is to add some commerciallydesirable, agronomically important trait to the plant. The exactbackcrossing protocol will depend on the characteristic or trait beingaltered to determine an appropriate testing protocol. Althoughbackcrossing methods are simplified when the characteristic beingtransferred is a dominant allele, a recessive allele may also betransferred. In this instance it may be necessary to introduce a test ofthe progeny to determine if the desired characteristic has beensuccessfully transferred.

[0128] Many single gene traits have been identified that are notregularly selected for in the development of a new inbred but that canbe improved by backcrossing techniques. Single gene traits may or maynot be transgenic, examples of these traits include but are not limitedto, male sterility, waxy starch, herbicide resistance, resistance forbacterial, fungal, or viral disease, insect resistance, male fertility,enhanced nutritional quality, industrial usage, yield stability andyield enhancement. These genes are generally inherited through thenucleus. Some known exceptions to this are the genes for male sterility,some of which are inherited cytoplasmically, but still act as singlegene traits. Several of these single gene traits are described in U.S.Pat. Nos. 5,777,196; 5,948,957 and 5,969,212, the disclosures of whichare specifically hereby incorporated by reference.

INDUSTRIAL APPLICABILITY

[0129] Sweet corn is usually used as fresh produce, canning or freezing,for human consumption. Corn is used as human food, livestock feed, andas raw material in industry. The food uses of corn, in addition to humanconsumption of corn kernels, include both products of dry- andwet-milling industries. The principal products of corn dry milling aregrits, meal and flour. The corn wet-milling industry can provide cornstarch, corn syrups, and dextrose for food use. Corn oil is recoveredfrom corn germ, which is a by-product of both dry- and wet-millingindustries.

[0130] Corn, including both grain and non-grain portions of the plant,is also used extensively as livestock feed, primarily for beef cattle,dairy cattle, hogs and poultry.

[0131] Industrial uses of corn include production of ethanol, cornstarch in the wet-milling industry and corn flour in the dry-millingindustry. The industrial applications of corn starch and flour are basedon functional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The corn starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds and other miningapplications.

[0132] Plant parts other than the grain of corn are also used inindustry, for example: stalks and husks are made into paper andwallboard and cobs are used for fuel and to make charcoal.

[0133] The seed of inbred corn line 1880S, the plant produced from theinbred seed, the hybrid corn plant produced from the crossing of theinbred, hybrid seed, and various parts of the hybrid corn plant andtransgenic versions of the foregoing, can be utilized for human food,livestock feed, and as a raw material in industry.

TABLES

[0134] In the tables that follow, the traits and characteristics ofinbred corn line 1880S are given in hybrid combination. The datacollected on inbred corn line 1880S is presented for the keycharacteristics and traits. The tables present yield test informationabout 1880S. 1880S was tested in several hybrid combinations at numerouslocations, with one or two replications per location. Information aboutthese hybrids, as compared to several check hybrids, is presented.

[0135] Tables 1, 2 and 3:

[0136] The first pedigree listed in the comparison group is the hybridcontaining 1880S. Information for each pedigree includes:

[0137] The pedigree is shown in column 1.

[0138] Column 2 shows the days to silk (SILK) which are based on thenumber of days from planting until 50% of the plants show silk.

[0139] Column 3 shows the ear length in centimeters for each of thehybrids and commercial checks.

[0140] Column 4 gives the ears/plant score and is recorded by using ascoring system of 1-5, defined as follows

[0141] 1=No marketable ears/plant

[0142] 3=1 marketable ear/plant

[0143] 5=2 marketable ears/plant

[0144] Column 5 gives the tip fill score and is recorded by using ascoring system of 1-5, defined as follows:

[0145] 1=>5 cm blank tip

[0146] 2=5 cm blank tip

[0147] 3=2.5 cm blank tip

[0148] 4=1.5 cm blank tip

[0149] 5=no blank tip, perfect tip fill

[0150] Column 6 gives the husk cover

[0151] 1=no husk cover, most ears are exposed

[0152] 2=<2 cm of husk cover, ears are barely covered, a few are exposed

[0153] 3=2-4 cm of husk cover

[0154] 4=4-7.5 cm of husk cover

[0155] 5=>7.5 cm of husk cover TABLE 1 Overall Comparisons Hybrid vs.Check Hybrids Location: 2001 at Belle Glade, FL Silk EarlengthEars/plant Tip Fill Husk Cover Pedigree I880S* I874WS 56 18.8 3 4 5I880S* 936376 56 20.5 4 3.8 3.5 As Compared to: Twin Star 57 19.2 3.54.8 5 Candy Store 55 19.5 3 4 2.8

[0156] TABLE 2 Overall Comparisons Hybrid vs. Check Hybrids Location:2001 at Los Mochis, Mexico Silk Ear length Ears/plant Tip Fill HuskCover Pedigree I880S* I874WS 83 16 13 4 3.5 I880S* 936376 80 17 3 3.5 4As Compared to: Twin Star 87 15.5 3 3.8 3 Candy Store 80 17 3 3.5 3

[0157] TABLE 3 Overall Comparisons Hybrid vs. Check Hybrids Location:2000 at Belle Glade, FL Silk Ear length Ears/plant Tip Fill Husk CoverPedigree I880S* I874WS 54 18.6 3.2 4.3 4.8 I880S* 936376 53 19.7 3.5 4.53.5 As Compared to: 57 18.2 3 4 5 Candy Store 52 18.8 3 3.5 2

[0158] Table 4:

[0159] The first pedigree listed in the comparison group is the hybridcontaining 1880S. Information for each pedigree includes:

[0160] The pedigree is shown in column 1.

[0161] The month and year of the data collection is shown in column 2

[0162] The location is shown column 3.

[0163] Column 4 shows the days to silk (SILK) which are based on thenumber of days from planting until 50% of the plants show silk.

[0164] Column 5 shows the ear length in centimeters for each of thehybrids and commercial checks.

[0165] Column 6 gives the ears/plant score and is recorded by using ascoring system of 1-5, defined as follows

[0166] 1=No marketable ears/plant

[0167] 3=1 marketable ear/plant

[0168] 5=2 marketable ears/plant

[0169] Column 7 gives the tip fill score and is recorded by using ascoring system of 1-5, defined as follows:

[0170] 1=>5 cm blank tip

[0171] 2=5 cm blank tip

[0172] 3=2.5 cm blank tip

[0173] 4=1.5 cm blank tip

[0174] 5=no blank tip, perfect tip fill

[0175] Column 8 gives the husk cover

[0176] 1=no husk cover, most ears are exposed

[0177] 2=<2 cm of husk cover, ears are barely covered, a few are exposed

[0178] 3=2-4 cm of husk cover

[0179] 4=4-7.5 cm of husk cover

[0180] 5=>7.5 cm of husk cover TABLE 4 OVERALL COMPARISONS Hybrid vs.Check Hybrids Month/ Ear Ears per Tip Husk Pedigree Year Location SilkLength Plant Fill Cover I880S*I874WS May 2001 Belle Glade, FL 56 18.8 34 5 Twin Star May 2001 Belle Glade, FL 57 19.2 3.5 4.8 5 I880S*I874WSMarch 2001 Los Mochis, Mex 83 16 3 4 3.5 Twin Star March 2001 LosMochis, Mex 87 15.5 3 3.8 3 I880S*I874WS March 2001 Queri, Chile 64 18.82.8 3.8 4 Twin Star March 2001 Queri, Chile 63 18.4 2.7 4 5 I880S*I874WSMay 2000 Belle Glade, FL 54 18.6 3.2 4.3 4.8 Twin Star May 2000 BelleGlade, FL 57 18.2 3 4 5 I880S*I874WS September 2000 Hall, NY 62 18.6 3 44 Twin Star September 2000 Hall, NY 63 18.6 2.8 4.5 2.5 I880S*I874WSAugust 2000 Sun Prairie, WI 66 20 3 4.8 3.5 Twin Star August 2000 SunPrairie, WI 66 18.5 3 4.8 3 I880S*I874WS August 2000 Nampa, ID 80 22 34.8 3 Twin Star August 2000 Nampa, ID 83 19.5 3 4.9 3 I880S*I874WSSeptember 2000 Davis, CA 58 20 3 4.8 3 Twin Star September 2000 Davis,CA 62 19 3 5 3 I880S*I874WS March 2000 Los Mochis, Mex 86 17.6 2.7 3.8 5Twin Star March 2000 Los Mochis, Mex 92 16.5 2.5 2.5 4 I880S*I874WS May1999 Belle Glade, FL 58 19 2.8 4.8 3.5 Twin Star May 1999 Belle Glade,FL 59 16 28 4.5 4.5 I880S*I874WS September 1999 Hall, NY 57 19.8 3 3.8 5Twin Star September 1999 Hall, NY 60 20.8 3 4.5 4.5 I880S*I874WSSeptember 1999 Sun Prairie, WI 63 20 3 4.8 3.5 Twin Star September 1999Sun Prairie, WI 58 19 3 4.8 3 I880S*I874WS August 1999 Nampa, ID 81 20 34.5 3 Twin Star August 1999 Nampa, ID 85 21 3 5 3 I880S*I874WS March1999 Los Mochis, Mex 89 18.6 3.1 3.8 5 Twin Star March 1999 Los Mochis,Mex 94 18.4 3.5 4.5 4.5

DEPOSIT INFORMATION

[0181] A deposit of the inbred corn seed of this invention is maintainedby Harris Moran Seed Company, 1832 Garrity Blvd, Nampa, Id. 83687.Access to this deposit will be available during the pendency of thisapplication to persons determined by the Commissioner of Patent andTrademarks to be entitled thereto under 37 CRF 1.14 and 35 USC 122. Uponallowance of any claims in this application, all restrictions on theavailability to the public of the variety will be irrevocably removed byaffording access to a deposit of at least 2,500 seeds of the samevariety with the American Type Culture Collection (ATCC), 10801University Boulevard, Manassas, Va. 20110.

[0182] Although the foregoing invention has been described in somedetail by way of illustration and example for purposes of clarity andunderstanding. However, it will be obvious that certain changes andmodifications such as single gene modifications and mutations,somaclonal variants, variant individuals selected from large populationsof the plants of the instant inbred and the like may be practiced withinthe scope of the invention, as limited only by the scope of the appendedclaims.

What is claimed is:
 1. Seed of corn inbred line designated 1880S,representative seed of said line having been deposited under ATCCAccession No. ______.
 2. A corn plant, or parts thereof, produced bygrowing the seed of claim
 1. 3. Pollen of the plant of claim
 2. 4. Anovule of the plant of claim
 2. 5. A corn plant, or parts thereof, havingall of the physiological and morphological characteristics of the cornplant of claim
 2. 6. The corn plant of claim 2, wherein said plant ismale sterile.
 7. A tissue culture of regenerable cells from the cornplant of claim
 2. 8. A tissue culture according to claim 7, the cells orprotoplasts of the tissue culture being from a tissue selected from thegroup consisting of leaves, pollen, embryos, roots, root tips, anthers,silks, flowers, kernels, ears, cobs, husks, and stalks.
 9. A corn plantregenerated from the tissue culture of claim 7, wherein the regeneratedplant is capable of expressing all the morphological and physiologicalcharacteristics of inbred line 1880S.
 10. A corn plant with all of thephysiological and morphological characteristics of corn inbred 1880S,wherein said corn plant is produced by a tissue culture process usingthe corn plant of claim 5 as the starting material for such a process.11. A method for producing a hybrid corn seed comprising crossing afirst inbred parent corn plant with a second inbred parent corn plantand harvesting the resultant hybrid corn seed, wherein said first inbredparent corn plant or second said parent corn plant is the corn plant ofclaim
 2. 12. A hybrid corn seed produced by the method of claim
 11. 13.A hybrid corn plant, or parts thereof, produced by growing said hybridcorn seed of claim
 12. 14. A corn seed produced by growing said cornplant of claim 13 and harvesting the resultant corn seed.
 15. An F₁hybrid seed produced by crossing the inbred corn plant according toclaim 2 with another, different corn plant.
 16. A hybrid corn plant, orits parts, produced by growing said hybrid corn seed of claim
 15. 17. Amethod for producing inbred 1880S, representative seed of which havebeen deposited under ATCC Accession No. ______, comprising: a) plantinga collection of seed comprising seed of a hybrid, one of whose parentsis inbred 1880S, said collection also comprising seed of said inbred; b)growing plants from said collection of seed; c) identifying inbredparent plants; d) controlling pollination in a manner which preservesthe homozygosity of said inbred parent plant; and e) harvesting theresultant seed.
 18. The process of claim 17 wherein step (c) comprisesidentifying plants with decreased vigor.
 19. A method for producing a1880S-derived corn plant, comprising: a) crossing inbred corn line1880S, representative seed of said line having been deposited under ATCCaccession number ______, with a second corn plant to yield progeny cornseed; and b) growing said progeny corn seed, under plant growthconditions, to yield said 1880S-derived corn plant.
 20. A 1880S-derivedcorn plant, or parts thereof, produced by the method of claim 19, said1880S-derived corn plant expressing a combination of at least two 1880Straits selected from the group consisting of: a good seedling vigor, agood seed quality, excellent husk cover, above average stay green,excellent pollen shed, medium flag leaves, good ear shape, good kernelrowing, Rp1D common rust resistance, Maize Dwarf Mosaic Virus (MDMV)resistance, tolerance to Stewart's Wilt, very good plant habit with astrong stalk for season long standability.and adapted to the Northwestregions of the United States.
 21. The method of claim 19, furthercomprising: c) crossing said 1880S-derived corn plant with itself oranother corn plant to yield additional 1880S-derived progeny corn seed;d) growing said progeny corn seed of step (c) under plant growthconditions, to yield additional 1880S-derived corn plants; and e)repeating the crossing and growing steps of (c) and (d) from 0 to 7times to generate further 1880S-derived corn plants.
 22. A further1880S-derived corn plant, or parts thereof, produced by the method ofclaim
 21. 23. The further 1880S-derived corn plant, or parts thereof, ofclaim 22, wherein said further 1880S-derived corn plant, or partsthereof, express a combination of at least two 1880S traits selectedfrom the group consisting of a good seedling vigor, a good seed quality,excellent husk cover, above average stay green, excellent pollen shed,medium flag leaves, good ear shape, good kernel rowing, Rp1D common rustresistance, Maize Dwarf Mosaic Virus (MDMV) resistance, tolerance toStewart's Wilt, very good plant habit with a strong stalk for seasonlong standability.and adapted to the Northwest regions of the UnitedStates.
 24. The method of claim 19, still further comprising utilizingplant tissue culture methods to derive progeny of said 1880S-derivedcorn plant.
 25. A 1880S-derived corn plant, or parts thereof, producedby the method of claim 24, said 1880S-derived corn plant expressing acombination of at least two 1880S traits selected from the groupconsisting of a good seedling vigor, a good seed quality, excellent huskcover, above average stay green, excellent pollen shed, medium flagleaves, good ear shape, good kernel rowing, Rp1D common rust resistance,Maize Dwarf Mosaic Virus (MDMV) resistance, tolerance to Stewart's Wilt,very good plant habit with a strong stalk for season longstandability.and adapted to the Northwest regions of the United States.26. The corn plant, or parts thereof, of claim 2, wherein the plant orparts thereof have been transformed so that its genetic materialcontains one or more transgenes operably linked to one or moreregulatory elements.
 27. A method for producing a corn plant thatcontains in its genetic material one or more transgenes, comprisingcrossing the corn plant of claim 26 with either a second plant ofanother corn line, or a non-transformed corn plant of the line 1880S, sothat the genetic material of the progeny that result from the crosscontains the transgene(s) operably linked to a regulatory element. 28.Corn plants, or parts thereof, produced by the method of claim
 27. 29. Acorn plant, or parts thereof, wherein at least one ancestor of said cornplant is the corn plant of claim 2, said corn plant expressing acombination of at least two 1880S traits selected from the groupconsisting of: a good seedling vigor, a good seed quality, excellenthusk cover, above average stay green, excellent pollen shed, medium flagleaves, good ear shape, good kernel rowing, Rp1D common rust resistance,Maize Dwarf Mosaic Virus (MDMV) resistance, tolerance to Stewart's Wilt,very good plant habit with a strong stalk for season longstandability.and adapted to the Northwest regions of the United States.30. A method for developing a corn plant in a corn plant breedingprogram using plant breeding techniques which include employing a cornplant, or its parts, as a source of plant breeding material comprising:using the corn plant, or its parts, of claim 2 as a source of saidbreeding material.
 31. The corn plant breeding program of claim 30wherein plant breeding techniques are selected from the group consistingof: recurrent selection, backcrossing, pedigree breeding, restrictionfragment length polymorphism enhanced selection, genetic marker enhancedselection, and transformation.
 32. A corn plant, or parts thereof,produced by the method of claim
 30. 33. The corn plant of claim 5,further comprising a single gene conversion where the gene confers acharacteristic selected from the group consisting of: male sterility,herbicide resistance, insect resistance, resistance to bacterial, fungalor viral disease and corn endosperm or quality.